Prognostic Significance of Head-and-Neck Cancer Biomarkers Previously Discovered and Identified Using iTRAQ-Labeling and Multidimensional Liquid Chromatography−Tandem Mass Spectrometry

Abstract

Diagnostic oncoproteomics is an emerging field; at present, studies on evaluation of prognostic utility of potential biomarkers identified using proteomic techniques are limited. Analysis with isobaric mass tags (iTRAQ) by multidimensional liquid chromatography-mass spectrometry (LC-MS/MS) to identify proteins that are differentially expressed in human head-and-neck/oral squamous cell carcinomas (HNOSCCs) versus noncancerous head-and-neck tissues has led to the discovery, identification, and verification of consistently increased expression of a panel of proteins, including stratifin (14-3-3sigma) and YWHAZ (14-3-3zeta), that may serve as potential cancer biomarkers. Herein, we describe the prognostic utility of these two candidate biomarkers for head-and-neck/oral squamous cell carcinoma (HNOSCC). To determine the clinical significance of stratifin and YWHAZ in head-and-neck tumorigenesis, the expressions of these two proteins were analyzed in HNOSCCs (51 cases) and nonmalignant tissues (39 cases) using immunohistochemistry. Significant increase in stratifin expression was observed in the HNOSCCs as compared to the nonmalignant mucosa [p=0.003, Odd's Ratio (OR)=3.8, 95% CI=1.6-9.2]. Kaplan-Meier survival analysis reveals correlation of stratifin overexpression with reduced disease-free survival of HNOSCC patients (p=0.06). The most intriguing finding is the significant decrease in median disease-free survival (13 months) in HNOSCC patients showing overexpression of both stratifin and YWHAZ proteins, as compared to patients that did not show overexpression of these proteins (median disease-free survival=38 months, p=0.019), underscoring their utility as adverse prognosticators for HNOSCCs. Co-immunoprecipitation assays show the formation of stratifin-YWHAZ heterodimers in HNOSCC cells and tissue samples, and interactions with NFkappaB, beta-catenin, and Bcl-2 proteins. These results suggest the involvement of these proteins in the development of head-and-neck cancer and their association with adverse disease outcome.

Enhanced Interferon Signaling Pathway in Oral Cancer Revealed by Quantitative Proteome Analysis of Microdissected Specimens Using 16O/18O Labeling and Integrated Two-dimensional LC-ESI-MALDI Tandem MS

“…To minimize technical variations and improve the reliability of protein quantification, a variety of sophisticated stable isotope labeling techniques have been developed for MS-based proteomics analysis, including chemical (32,33), metabolic (34,35), and enzymatic (36 -38) labeling techniques. Improvements in the quality and accuracy of quantitative proteomics analysis via such stable isotope labeling strategies have facilitated the discovery of potential tumor markers in malignancies such as OSCC/HNSCC (16,39,40).…”

Clinical Significance of 14-3-3 Zeta in Human Esophageal Cancer

“…Recently, Matta et al verified the consistently increased expression of 14-3-3 zeta and sigma proteins in human head-and-neck/oral squamous cell carcinomas versus noncancerous headand-neck tissues (36). The authors also suggested the involvement of these proteins in the development of headand-neck cancer and their association with adverse disease outcome.…”

Loss of DLC1 is an independent prognostic factor in patients with oral squamous cell carcinoma

“…The systematic and rigorous assessment of positive PVs and negative PVs for prognostic biomarker was carried out as described earlier by us. 38 Heagerty and Zheng method of time-dependent receiver operator curve and area under the curve was used for the survival model. 40 The R-package risk set ROC was used to apply the standard Cox regression output and obtain estimates of time-dependent sensitivity and specificity, and time-dependent receiver operator curves.…”

“…As per the hospital protocol, oral squamous cell carcinoma patients with T 1 and T 2 tumors were treated with radical surgery alone, whereas the majority of patients with T 3 and T 4 disease were treated with radical surgery followed by postoperative radical radiotherapy as described by us. 38 The patients were revisited clinically on a regular basis and the time to recurrence was recorded. If a patient died, the survival time was censored at the time of death; the medical history, clinical examination, and radiological evaluation were used to determine whether the death had resulted from recurrent cancer (relapsing patients) or from any other causes.…”

“…37 Patient demographic, clinical, and pathological data were recorded in a pre-designed performa as described previously. 38 The information documented included clinical TNM staging (tumor, node, and metastasis based on the Union International Center le Cancer TNM classification of malignant tumors 1998), site of the lesion, histopathological grade, age, gender, treatment, and tobacco consumption habits.…”